Report of the cyanotoxins cylindrospermopsin and deoxy-cylindrospermopsin from Raphidiopsis mediterranea Skuja (Cyanobacteria/Nostocales)

A filamentous cyanobacterium isolated from the plankton of a eutrophic reservoir in Queensland (Australia) was, based on morphological features, putatively identified as Raphidiopsis mediterranea Skuja. Strain FSS1-150/1 was screened by HPLC MS/MS for a number of common cyanotoxins and was shown to produce both cylindrospermopsin (CYN) and deoxy-cylindrospermopsin (deoxy-CYN) at concentrations of 917 and 1065 μg g−1 dry weight respectively. Evidence for CYN synthesis by strain FSS1-150/1 was further supported by PCR amplification of a fragment of the CyrC gene involved in CYN biosynthesis. Subsequent phylogenetic analyses using a partial sequence of the 16S rRNA gene confirmed its identification and showed that strain FSS1-150/1 was closely related to strains of R. mediterranea and R. curvata. These results provide the first evidence of the production of CYN and deoxy-CYN by R. mediterranea and it is the second species of the genus Raphidiopsis known to produce these potent cyanotoxins.

▸ We isolated a strain of the bloom forming cyanobacterium Raphidiopsis mediterranea Skuja. ▸ Evidence is provided which shows that it produces the cyanotoxins cylindrospermopsin and deoxy-cylindrospermopsin. ▸ This is the first evidence of the production of cyanotoxins by this species.